Each institution will display treasures from archival collections, architecture firms and private collections, and host companion programming. Unbuilt San Francisco at the College of Environmental Design is a vivid history lesson, showing viewers a shadow city and phantom skyline. The curators explore why a building does not take brick-and-mortar form, from economic hubris to community resistance, and how an unrealized structure can shape what follows. The exhibition is also intended to engage students. A section on "First Takes" explores the early incarnations of buildings that do exist, and their passage from ideal to incarnation. "Rhetorical Unbuilt" looks at the other extreme of architecture — plans meant to put new ideas before the public, stir debate, and prod us to consider other ways of living in an age that faces environmental and societal pressures we could not have imagined a century ago. One of the most fascinating designs in the show is a 1969 plan to fill the Sutro Bath ruins with condominiums — exactly the sort of proposal that spurred the "green" activism of the era and helped spawn the Golden Gate National Recreation Area.